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Q21
Write the chemical formula and name of the compound which is the active ingredient of all alcoholic drinks. List its two uses. Write chemical equation and name of the product formed when this compound reacts with -
(i) sodium metal
(ii) hot concentrated sulphuric acid

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Q22
What is methane? Draw its electron dot structure. Name the type of bonds formed in this compound. Why are such compounds:
(i) poor conductors of electricity? and
(ii) have low melting and boiling points?
What happens when this compound bums in oxygen?

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Q23
(a) Write chemical equations for the following reactions:
(i) Calcium metal reacts with water
(ii) Cinnabar is heated in the presence of air.
(iii) Manganese dioxide is heated with aluminum powder.

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Q24
(b) What are alloys? List two properties of alloys.

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Q25
An object is placed at distance of 30 cm from a concave lens of focal length 30 cm.
(i) Use lens to determine the distance of the image form the lens.
(ii) List four characteristics of the image (nature, position, size, erected/inverted) in this case.
(iii) Draw a labelled diagram to justify your answer if part (ii),

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Q26
(a) With the help of a suitable circuit diagram prove that the reciprocal of the equivalent resistance if a group of resistances joined in parallel is equal to the sum of reciprocals of the individual resistances.

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Q27
(b) In an electric circuit two resistors of 12 Ω each are joined in parallel to a 6 V battery. Find the current drawn from the battery.

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Q28
An electric lamp of resistance 20 Ω and a conductor of resistance 4 Ω are connected to a 6 V battery as shown in the circuit. Calculate:
(a) the total resistance of the circuit,
(b) the current through the circuit,
(c) the potential difference across the (i) electric lamp and (ii) conductor, and
(d) power of the lamp.

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Q29
What is a solenoid? Draw the pattern of magnetic field lines of (i) a current carrying solenoid and (ii) a bar magnet. List two distinguishing features between the two fields.

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Q30
Define pollination. Explain the different types of pollination. List two agents of pollination? How does suitable pollination lead to fertilization?

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2019

Q21
Write the chemical formula and name of the compound which is the active ingredient of all alcoholic drinks. List its two uses. Write chemical equation and name of the product formed when this compound reacts with -
(i) sodium metal
(ii) hot concentrated sulphuric acid

Solution

Q22
What is methane? Draw its electron dot structure. Name the type of bonds formed in this compound. Why are such compounds:
(i) poor conductors of electricity? and
(ii) have low melting and boiling points?
What happens when this compound bums in oxygen?

Solution

Q23
(a) Write chemical equations for the following reactions:
(i) Calcium metal reacts with water
(ii) Cinnabar is heated in the presence of air.
(iii) Manganese dioxide is heated with aluminum powder.

Solution

Q24
(b) What are alloys? List two properties of alloys.

Solution

Solution

Q26
(a) With the help of a suitable circuit diagram prove that the reciprocal of the equivalent resistance if a group of resistances joined in parallel is equal to the sum of reciprocals of the individual resistances.

Solution

Q27
(b) In an electric circuit two resistors of 12 Ω each are joined in parallel to a 6 V battery. Find the current drawn from the battery.

Solution

Solution

Q29
What is a solenoid? Draw the pattern of magnetic field lines of (i) a current carrying solenoid and (ii) a bar magnet. List two distinguishing features between the two fields.

Solution

Q30
Define pollination. Explain the different types of pollination. List two agents of pollination? How does suitable pollination lead to fertilization?

Solution

Subjects

2019

Q21 Write the chemical formula and name of the compound which is the active ingredient of all alcoholic drinks. List its two uses. Write chemical equation and name of the product formed when this compound reacts with - (i) sodium metal (ii) hot concentrated sulphuric acid

Solution

Q22 What is methane? Draw its electron dot structure. Name the type of bonds formed in this compound. Why are such compounds: (i) poor conductors of electricity? and (ii) have low melting and boiling points? What happens when this compound bums in oxygen?

Solution

Q23 (a) Write chemical equations for the following reactions: (i) Calcium metal reacts with water (ii) Cinnabar is heated in the presence of air. (iii) Manganese dioxide is heated with aluminum powder.

Solution

Q24 (b) What are alloys? List two properties of alloys.

Solution

Solution

Q26 (a) With the help of a suitable circuit diagram prove that the reciprocal of the equivalent resistance if a group of resistances joined in parallel is equal to the sum of reciprocals of the individual resistances.

Solution

Q27 (b) In an electric circuit two resistors of 12 Ω each are joined in parallel to a 6 V battery. Find the current drawn from the battery.

Solution

Solution

Q29 What is a solenoid? Draw the pattern of magnetic field lines of (i) a current carrying solenoid and (ii) a bar magnet. List two distinguishing features between the two fields.

Solution

Q30 Define pollination. Explain the different types of pollination. List two agents of pollination? How does suitable pollination lead to fertilization?

Solution

Subjects

Q21
Write the chemical formula and name of the compound which is the active ingredient of all alcoholic drinks. List its two uses. Write chemical equation and name of the product formed when this compound reacts with -
(i) sodium metal
(ii) hot concentrated sulphuric acid

Q22
What is methane? Draw its electron dot structure. Name the type of bonds formed in this compound. Why are such compounds:
(i) poor conductors of electricity? and
(ii) have low melting and boiling points?
What happens when this compound bums in oxygen?

Q23
(a) Write chemical equations for the following reactions:
(i) Calcium metal reacts with water
(ii) Cinnabar is heated in the presence of air.
(iii) Manganese dioxide is heated with aluminum powder.

Q24
(b) What are alloys? List two properties of alloys.

Q26
(a) With the help of a suitable circuit diagram prove that the reciprocal of the equivalent resistance if a group of resistances joined in parallel is equal to the sum of reciprocals of the individual resistances.

Q27
(b) In an electric circuit two resistors of 12 Ω each are joined in parallel to a 6 V battery. Find the current drawn from the battery.

Q29
What is a solenoid? Draw the pattern of magnetic field lines of (i) a current carrying solenoid and (ii) a bar magnet. List two distinguishing features between the two fields.

Q30
Define pollination. Explain the different types of pollination. List two agents of pollination? How does suitable pollination lead to fertilization?